<template>
  <div>
    <!-- 无id时, 可以使用index(反正也是就地更新) -->
    <div style="display: inline-block" v-for="(item,index) in arr" :key="index">
         <input type="checkbox" v-model="isNum" :value="item" />{{ item }}
    </div>
    <p>你选中的元素, 累加的值和为: {{sum}}</p>
  </div>
</template>

<script>
export default {
  data() {
    return {
      arr :[9, 15, 19, 25, 29, 31, 48, 57, 62, 79, 87],
      isNum:[]
    }
  },
  computed: {
   sum() {
    return this.isNum.reduce((sum,item) => sum +item , 0)
   } 
  }
};
</script>